CYP2E1 regulates the development of radiation-induced pulmonary fibrosis via ER stress- and ROS-dependent mechanisms

Radio-miRs: a comprehensive view of radioresistance-related microRNAs

Radiotherapy is a key treatment option for a wide variety of human tumors, employed either alone or alongside with other therapeutic interventions. Radiotherapy uses high-energy particles to destroy tumor cells, blocking their ability to divide and proliferate. The effectiveness of radiotherapy is due to genetic and epigenetic factors that determine how tumor cells respond to ionizing radiation. These factors contribute to the establishment of resistance to radiotherapy, which increases the risk of poor clinical prognosis of patients. Although the mechanisms by which tumor cells induce radioresistance are unclear, evidence points out several contributing factors including the overexpression of DNA repair systems, increased levels of reactive oxygen species, alterations in the tumor microenvironment, and enrichment of cancer stem cell populations. In this context, dysregulation of microRNAs or miRNAs, critical regulators of gene expression, may influence how tumors respond to radiation. There is increasing evidence that miRNAs may act as sensitizers or enhancers of radioresistance, regulating key processes such as the DNA damage response and the cell death signaling pathway. Furthermore, expression and activity of miRNAs have shown informative value in overcoming radiotherapy and long-term radiotoxicity, revealing their potential as biomarkers. In this review, we will discuss the molecular mechanisms associated with the response to radiotherapy and highlight the central role of miRNAs in regulating the molecular mechanisms responsible for cellular radioresistance. We will also review radio-miRs, radiotherapy-related miRNAs, either as sensitizers or enhancers of radioresistance that hold promise as biomarkers or pharmacological targets to sensitize radioresistant cells.

Crosstalk between lipid metabolism and EMT: emerging mechanisms and cancer therapy

Lipids are the key component of all membranes composed of a variety of molecules that transduce intracellular signaling and provide energy to the cells in the absence of nutrients. Alteration in lipid metabolism is a major factor for cancer heterogeneity and a newly identified cancer hallmark. Reprogramming of lipid metabolism affects the diverse cancer phenotypes, especially epithelial-mesenchymal transition (EMT). EMT activation is considered to be an essential step for tumor metastasis, which exhibits a crucial role in the biological processes including development, wound healing, and stem cell maintenance, and has been widely reported to contribute pathologically to cancer progression. Altered lipid metabolism triggers EMT and activates multiple EMT-associated oncogenic pathways. Although the role of lipid metabolism-induced EMT in tumorigenesis is an attractive field of research, there are still significant gaps in understanding the underlying mechanisms and the precise contributions of this interplay. Further study is needed to clarify the specific molecular mechanisms driving the crosstalk between lipid metabolism and EMT, as well as to determine the potential therapeutic implications. The increased dependency of tumor cells on lipid metabolism represents a novel therapeutic target, and targeting altered lipid metabolism holds promise as a strategy to suppress EMT and ultimately inhibit metastasis.

A Novel Cytochrome P450 2E1 Inhibitor Q11 Is Effective on Lung Cancer via Regulation of the Inflammatory Microenvironment

Lung cancer is the leading cause of death among all cancers. A persistent chronic inflammatory microenvironment is highly correlated with lung cancer. However, there are no anti-inflammatory agents effective against lung cancer. Cytochrome P450 2E1 (CYP2E1) plays an important role in the inflammatory response. Here, it is found that CYP2E1 is significantly higher in the peritumoral tissue of non-small cell lung cancer (NSCLC) patients and lung tumor growth is significantly impeded in Cyp2e1-/- mice. The novel CYP2E1 inhibitor Q11, 1-(4-methyl-5-thialzolyl) ethenone, is effective in the treatment of lung cancer in mice, which can inhibit cancer cells by changing macrophage polarization rather than directly act on the cancer cells. It is also clarify that the benefit of Q11 may associated with the IL-6/STAT3 and MAPK/ERK pathways. The data demonstrate that CYP2E1 may be a novel inflammatory target and that Q11 is effective on lung cancer by regulation of the inflammatory microenvironment. These findings provide a molecular basis for targeting CYP2E1 and illustrate the potential druggability of the CYP2E1 inhibitor Q11.

Exploration of molecular mechanism underlying protective effect of astragaloside IV against radiation-induced lung injury by suppressing ferroptosis

In this study, we aimed to investigate the pharmacological effects and underlying mechanisms of astragaloside IV (AS IV) against radiation-induced lung injury. We established experimental models of radiation-induced lung injury and observed the effect of AS IV on cell viability, cell death, inflammatory responses and ferroptosis. Accordingly, we found that AS IV restored the suppressed cell viability and promoted cell death induced by X-ray irradiation. Moreover, radiation-induced up-regulation of lactate dehydrogenase (LDH) release, ferroptosis, reactive oxygen species (ROS) and inflammatory responses were also restored by AS IV in a dose-dependent manner. Besides, in radiation-induced lung injury C57BL/6 mice, AS IV evidently alleviated lung injury and promoted the survival rate of lung-injured mice. And the ferroptosis level in mice lung tissues were also alleviated by the administration of AS IV in a dose-dependent manner. As a conclusion, by comparing the changes of ferroptosis, ROS and inflammatory responses in the experimental models, we validated that AS IV could inhibit inflammatory responses and cell injury in the treatment of radiation-induced lung injury by suppressing ferroptosis. This finding not only find potentially effective treatments to mitigate radiation-induced lung injury, but also provides supporting evidence for clinical application of AS IV to improve the management of radiation-treated patients and minimize the associated lung complications or other adverse effects. Moreover, as inflammation and ROS are key contributors to tissue damage in various diseases, our study suggested the potential application of AS IV in the treatments for other diseases.

The CYP2E1 inhibitor Q11 ameliorates LPS-induced sepsis in mice by suppressing oxidative stress and NLRP3 activation

Sepsis is an infection-induced, multi-organ system failure with a pathophysiology related to inflammation and oxidative stress. Increasing evidence indicates that cytochrome P450 2E1 (CYP2E1) is involved in the incidence and development of inflammatory diseases. However, a role for CYP2E1 in lipopolysaccharide (LPS)-induced sepsis has not been completely explored. Here we use Cyp2e1 knockout (cyp2e1-/-) mice to determine if CYP2E1 could be a therapeutic target for sepsis. We also evaluated the ability of Q11, a new specific CYP2E1 inhibitor, to prevent and ameliorate LPS-induced sepsis in mice and in LPS-treated J774A.1 and RAW264.7 cells. Cyp2e1 deletion significantly reduced hypothermia, multi-organ dysfunction and histological abnormalities in LPS-treated mice; consistent with this finding, the CYP2E1 inhibitor Q11 significantly prolonged the survival time of septic mice and ameliorated multi-organ injury induced by LPS. CYP2E1 activity in liver correlated with indicators of multi-organ injury, such as the level of lactate dehydrogenase (LDH) and blood urea nitrogen (BUN) (P<0.05). Q11 significantly suppressed the expression of NLRP3 in tissues after LPS injection; in vitro studies revealed that activation of NLRP3 signaling and increase of ROS was attenuated by Q11 in LPS-stimulated macrophages, which was reflected by reduced expression of caspase-1 and formation of ASC specks. Overall, our results indicate that Q11 improves the survival of mice with LPS-induced sepsis and attenuates sepsis-induced multiple-organ injury, suggesting that CYP2E1 could be a therapeutic target for sepsis.

Xenobiotic-sensing nuclear receptors as targets for phthalates-induced lung injury and antagonism of lycopene

Phthalates are extensively used in the production of plastics products and have been verified to induce lung injury. Lycopene (LYC) has proved an effective preventive and can be utilized to prevent phthalates-induced toxicity. However, the role of phthalate in pathogenesis of lung injury remain poorly researched, and little work has been devoted whether LYC could alleviate phthalate-induced lung toxicity via modulating nuclear xenobiotic receptors (NXRs) response. Here, di (2-ethylhexyl) phthalate (DEHP) is used as the representative of phthalates for further studies on toxicity of phthalates and the antagonistic role of LYC in phthalates-induced lung injury. We found that DEHP exposure caused alveoli destruction and alveolar epithelial cells type II damage. Mechanistically, DEHP exposure increased nuclear accumulation of aryl hydrocarbon receptor (AHR) and its downstream genes level, including cytochrome P450-dependent monooxygenase (CYP) 1A1 and CYP1B1. Constitutive androstane receptor (CAR) and their downstream gene level, including CYP2E1 are also increased after phthalates exposure. Significantly, LYC supplementation relieves lung injury from DEHP exposure by inhibiting the activation of NXRs. We confirm that NXRs plays a key role in phthalates-induced lung injury. Our study showed that LYC may have a positive role in alleviating the toxicity effects of phthalates, which provides an effective strategy for revising phthalates-induced injury.

The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells

Radiation-induced pulmonary fibrosis (RIPF) is a common consequence of radiation for thoracic tumors, and is accompanied by gradual and irreversible organ failure. This severely reduces the survival rate of cancer patients, due to the serious side effects and lack of clinically effective drugs and methods. Radiation-induced pulmonary fibrosis is a dynamic process involving many complicated and varied mechanisms, of which alveolar type II epithelial (AT2) cells are one of the primary target cells, and the epithelial-mesenchymal transition (EMT) of AT2 cells is very relevant in the clinical search for effective targets. Therefore, this review summarizes several important signaling pathways that can induce EMT in AT2 cells, and searches for molecular targets with potential effects on RIPF among them, in order to provide effective therapeutic tools for the clinical prevention and treatment of RIPF.

NUPR1 contributes to radiation resistance by maintaining ROS homeostasis via AhR/CYP signal axis in hepatocellular carcinoma

BACKGROUND

Radiotherapy (RT) is one of the major therapeutic approaches to hepatocellular carcinoma (HCC). Ionizing radiation (IR) inducing the generation of reactive oxygen species (ROS) leads to a promising antitumor effect. However, the dysregulation of the redox system often causes radioresistance and impairs the efficacy of RT. Increasing evidence indicates that nuclear protein 1 (NUPR1) plays a critical role in redox reactions. In this study, we aim to explore the role of NUPR1 in maintaining ROS homeostasis and radioresistance in HCC.

METHODS

The radioresistant role of NUPR1 was determined by colony formation assay, comet assay in vitro, and xenograft tumor models in vivo. Probes for ROS, apoptosis assay, and lipid peroxidation assay were used to investigate the functional effect of NUPR1 on ROS homeostasis and oxidative stress. RNA sequencing and co-immunoprecipitation assay were performed to clarify the mechanism of NUPR1 inhibiting the AhR/CYP signal axis. Finally, we analyzed clinical specimens to assess the predictive value of NUPR1 and AhR in the radiotherapeutic efficacy of HCC.

RESULTS

We demonstrated that NUPR1 was upregulated in HCC tissues and verified that NUPR1 increased the radioresistance of HCC in vitro and in vivo. NUPR1 alleviated the generation of ROS and suppressed oxidative stress, including apoptosis and lipid peroxidation by downregulating cytochrome P450 (CYP) upon IR. ROS scavenger N-acetyl-L-cysteine (NAC) and CYP inhibitor alizarin restored the viability of NUPR1-knockdown cells during IR. Mechanistically, the interaction between NUPR1 and aryl hydrocarbon receptor (AhR) promoted the degradation and decreased nuclear translation of AhR via the autophagy-lysosome pathway, followed by being incapable of CYP's transcription. Furthermore, genetically and pharmacologically activating AhR abrogated the radioresistant role of NUPR1. Clinical data suggested that NUPR1 and AhR could serve as novel biomarkers for predicting the radiation response of HCC.

CONCLUSIONS

Our findings revealed the role of NUPR1 in regulating ROS homeostasis and oxidative stress via the AhR/CYP signal axis upon IR. Strategies targeting the NUPR1/AhR/CYP pathway may have important clinical applications for improving the radiotherapeutic efficacy of HCC.

Non-coding RNA in idiopathic interstitial pneumonia and Covid-19 pulmonary fibrosis

Pulmonary fibrosis is the key feature of majority of idiopathic interstitial pneumonias (IIPs) as well as many patients with post-COVID-19. The pathogenesis of pulmonary fibrosis is a complex molecular process that involves myriad of cells, proteins, genes, and regulatory elements. The non-coding RNA mainly miRNA, circRNA, and lncRNA are among the key regulators of many protein coding genes and pathways that are involved in pulmonary fibrosis. Identification and molecular mechanisms, by which these non-coding RNA molecules work, are crucial to understand the molecular basis of the disease. Additionally, elucidation of molecular mechanism could also help in deciphering a potential diagnostic/prognostic marker as well as therapeutic targets for IIPs and post-COVID-19 pulmonary fibrosis. In this review, we have provided the latest findings and discussed the role of these regulatory elements in the pathogenesis of pulmonary fibrosis associated with Idiopathic Interstitial Pneumonia and Covid-19.

A genome-wide association study identifying single nucleotide polymorphisms in the PPFIBP2 gene was predictive for interstitial lung disease in rheumatoid arthritis patients

Objective

Genetic polymorphisms might serve as useful prognostic markers for the timely diagnosis of RA. The purpose of this study was to identify genomic factors predictive of the occurrence of interstitial lung disease (ILD) in RA by performing a genome-wide association study of genetic variants, including single nucleotide polymorphisms (SNPs).

Methods

The study population included 306 RA patients. All patients were treated with conventional DMARDs, including 6–16 mg MTX per week. Clinical data and venous blood samples were collected from all patients before administration of DMARDs. A total of 278 347 SNPs were analysed to determine their association with ILD occurrence.

Results

Several SNPs were strongly associated with ILD occurrence (P < 10⁻⁵). rs6578890, which is located on chromosome 11 in the intronic region of the gene encoding tyrosine phosphatase receptor type F polypeptide-interacting protein-binding protein 2 (PPFIBP2), showed the strongest association with ILD occurrence (odds ratio 4.32, P = 10^−7.93).

Conclusion

PPFIBP2 could be a useful genetic marker for occurrence of interstitial pneumonia in RA patients and might help to identify the risk of ILD occurrence before RA treatment, thereby improving patient outcomes.

A novel circRNA-SNP may increase susceptibility to silicosis

In this study, we aimed to reveal the association between circRNA-related single nucleotide polymorphisms (SNPs) with the susceptibility of silicosis. To achieve this goal, a silicosis-related GWAS was constructed to select the candidate SNPs, and circBase database was utilized to select the promising SNPs which may locate on circRNAs. In addition, the eQTL analysis between the SNPs and located genes was performed to select the candidate SNPs. Finally, the association between candidate SNPs with the susceptibility of silicosis was validated. As a result, we firstly selected 10,922 SNPs with P < 1 × 10^-3 through the silicosis-related GWAS. Among which, 1,752 SNPs were identified that may locate on 2,660 circRNAs. After the MAF evaluation and the sequences checking, we obtained 94 SNPs and related 105 circRNAs. EQTL analysis indicated that 7 circRNA-SNPs might regulate the expression of located genes. Subsequently, a strong association was found between variant A of rs17115143 and silicosis risk in the validation stage (OR= 1.68, P = 0.032). Combination of the GWAS data and Taqman genotyping data also revealed a strong association between rs17115143 and silicosis risk in both dominant and additive models (dom: OR= 1.96, P = 3.98 × 10^-4; add: OR= 1.40, P = 3.06 × 10^-4). In conclusion, the variant A allele of circRNA-SNP rs17115143 could be a risk factor in the progression of silicosis. And related 6 circRNAs may function as novel biomarkers for the diagnostic of silicosis. Further researches to explore the biological mechanisms of rs17115143 related 6 circRNAs in the regulation of silicosis are warranted.

A missing piece of the puzzle in pulmonary fibrosis: anoikis resistance promotes fibroblast activation

Background

Pulmonary fibrosis initiates a pneumonic cascade that leads to fibroblast dysfunction characterized by excess proliferation. Anoikis is a physiological process that ensures tissue development and homeostasis. Researchers have not clearly determined whether disruption of anoikis is involved in pulmonary fibrosis.

Results

Here, we investigated the mechanism by which silica induces fibroblast activation via anoikis resistance and subsequent fibrosis. Anoikis of lung fibroblasts, alveolar epithelial cells and endothelial cells during the process of fibrosis was detected using CCK-8, western blot, cell count and flow cytometry (FCM) assays. Although the three cell types showed similar increases in proliferation, the expression of NTRK2, a marker of anoikis resistance, was upregulated specifically in fibroblasts, indicating the unique proliferation mechanism of fibroblasts in pulmonary fibrosis, which may be related to anoikis resistance. Furthermore, the CRISPR/Cas9 system was used to investigate the molecular mechanism of anoikis resistance; the SiO₂-induced inflammatory response activated the MAPK/PI3K signaling pathway in lung fibroblasts and then induced the expression of the ZC3H4 protein, which specifically mediated anoikis resistance, followed by pulmonary fibrosis.

Conclusions

The current study revealed a specific pattern of fibroblast proliferation, and strategies targeting anoikis resistance may inhibit the pathological process of pulmonary fibrosis. This result provides a new approach for treating pulmonary fibrosis and new insights into the potential application of ZC3H4 in the development of novel therapeutic strategies for mitigating pulmonary fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00761-2.

BEX1 and BEX4 Induce GBM Progression through Regulation of Actin Polymerization and Activation of YAP/TAZ Signaling

GBM is a high-grade cancer that originates from glial cells and has a poor prognosis. Although a combination of surgery, radiotherapy, and chemotherapy is prescribed to patients, GBM is highly resistant to therapies, and surviving cells show increased aggressiveness. In this study, we investigated the molecular mechanism underlying GBM progression after radiotherapy by establishing a GBM orthotopic xenograft mouse model. Based on transcriptomic analysis, we found that the expression of BEX1 and BEX4 was upregulated in GBM cells surviving radiotherapy. We also found that upregulated expression of BEX1 and BEX4 was involved in the formation of the filamentous cytoskeleton and altered mechanotransduction, which resulted in the activation of the YAP/TAZ signaling pathway. BEX1- and BEX4-mediated YAP/TAZ activation enhanced the tumor formation, growth, and radioresistance of GBM cells. Additionally, latrunculin B inhibited GBM progression after radiotherapy by suppressing actin polymerization in an orthotopic xenograft mouse model. Taken together, we suggest the involvement of cytoskeleton formation in radiation-induced GBM progression and latrunculin B as a GBM radiosensitizer.

Downregulated CLIP3 induces radioresistance by enhancing stemness and glycolytic flux in glioblastoma

Background

Glioblastoma Multiforme (GBM) is a malignant primary brain tumor in which the standard treatment, ionizing radiation (IR), achieves a median survival of about 15 months. GBM harbors glioblastoma stem-like cells (GSCs), which play a crucial role in therapeutic resistance and recurrence.

Methods

Patient-derived GSCs, GBM cell lines, intracranial GBM xenografts, and GBM sections were used to measure mRNA and protein expression and determine the related molecular mechanisms by qRT-PCR, immunoblot, immunoprecipitation, immunofluorescence, OCR, ECAR, live-cell imaging, and immunohistochemistry. Orthotopic GBM xenograft models were applied to investigate tumor inhibitory effects of glimepiride combined with radiotherapy.

Results

We report that GSCs that survive standard treatment radiation upregulate Speedy/RINGO cell cycle regulator family member A (Spy1) and downregulate CAP-Gly domain containing linker protein 3 (CLIP3, also known as CLIPR-59). We discovered that Spy1 activation and CLIP3 inhibition coordinately shift GBM cell glucose metabolism to favor glycolysis via two cellular processes: transcriptional regulation of CLIP3 and facilitating Glucose transporter 3 (GLUT3) trafficking to cellular membranes in GBM cells. Importantly, in combination with IR, glimepiride, an FDA-approved medication used to treat type 2 diabetes mellitus, disrupts GSCs maintenance and suppresses glycolytic activity by restoring CLIP3 function. In addition, combining radiotherapy and glimepiride significantly reduced GBM growth and improved survival in a GBM orthotopic xenograft mouse model.

Conclusions

Our data suggest that radioresistant GBM cells exhibit enhanced stemness and glycolytic activity mediated by the Spy1-CLIP3 axis. Thus, glimepiride could be an attractive strategy for overcoming radioresistance and recurrence by rescuing CLIP3 expression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02077-4.

Effects of Real-Ambient PM2.5 Exposure on Lung Damage Modulated by Nrf2-/

Previous studies have shown that long-term exposure to fine particulate matter (PM_2.5) increases the morbidity and mortality of pulmonary diseases such as asthma, chronic obstructive pulmonary disease and pulmonary emphysema. Oxidative stress and inflammation play key roles in pulmonary damage caused by PM_2.5. Nuclear factor erythroid 2-related factor 2 (Nrf2) could regulate the expression of antioxidant and anti-inflammatory genes and is pivotal for protection against PM_2.5-induced oxidative stress. In this study, a real-ambient exposure system was constructed with the outdoor ambient air in north China. Wild-type (WT) and Nrf2^−/− (KO) mice were exposed to the real-ambient system for six weeks. After PM_2.5 exposure, our data showed that the levels of inflammatory factors and malondialdehyde were significantly increased in WT and KO mice. Moreover, the lung function and pathological phenotype of the WT mice were altered but there was no obvious change in the Nrf2^−/− mice. To further explore the potential molecular mechanisms, we performed RNA-sequencing. The RNA-sequence analysis results showed that the CYP450 pathway in the first ten pathways of KEGG was related to the metabolism of PM_2.5. In WT and KO mice, the expression of CYP2E1 in the CYP450 pathway showed opposite trends after PM_2.5 exposure. The data showed that the expression of the CYP2E1 gene in WT-PM mice increased while it decreased in KO-PM; the expression of the CYP2E1 protein showed a similar trend. CYP2E1 is primarily distributed in the endoplasmic reticulum (ER) where it could metabolize various exogenous substances attached to PM_2.5 and produce highly toxic oxidation products closely related to ER stress. Consistently, the expression level of GRP94, a biomarker of ER stress, was increased in WT mice and reduced in KO mice under PM_2.5 exposure. Persistent ER stress is a mechanism that causes lung damage under PM_2.5 exposure. Nrf2 facilitates lung injury during PM_2.5 exposure and CYP2E1 metabolism is involved in this process.

Characterization of an endoplasmic reticulum stress-related signature to evaluate immune features and predict prognosis in glioma

Endoplasmic reticulum (ER) stress has considerable impact on cell growth, proliferation, metastasis, invasion, angiogenesis and chemoradiotherapy resistance in various cancers. However, the effect of ER stress on the outcomes of glioma patients remains unclear. In this study, we established an ER stress risk model based on The Cancer Genome Atlas (TCGA) glioma data set to reflect immune characteristics and predict the prognosis of glioma patients. Survival analysis indicated that there were significant differences in the overall survival (OS) of glioma patients with different ER stress-related risk scores. Moreover, the ER stress-related risk signature, which was markedly associated with the clinicopathological properties of glioma patients, could serve as an independent prognostic indicator. Functional enrichment analysis revealed that the risk model correlated with immune and inflammation responses, as well as biosynthesis and degradation. In addition, the ER stress-related risk model indicated an immunosuppressive microenvironment. In conclusion, we present an ER stress risk model that is an independent prognostic factor and indicates the general immune characteristics in the glioma microenvironment.

The role of cytochrome P450 (CYP) enzymes in hyperoxic lung injury

INTRODUCTION

Hyperoxic lung injury is a condition that can occur in patients in need of supplemental oxygen, such as premature infants with bronchopulmonary dysplasia or adults with acute respiratory distress syndrome. Cytochrome P450 (CYP) enzymes play critical roles in the metabolism of endogenous and exogenous compounds.

AREAS COVERED

Through their complex pathways, some subfamilies of these enzymes may contribute to or protect against hyperoxic lung injury. Oxidative stress from reactive oxygen species (ROS) production is most likely a major contributor of hyperoxic lung injury. CYP1A enzymes have been shown to protect against hyperoxic lung injury while CYP1B enzymes seem to contribute to it. CYP2J2 enzymes help protect against hyperoxic lung injury by triggering EET production, thereby, increasing antioxidant enzymes. The metabolism of arachidonic acid to ω-terminal hydroxyeicosatetraenoic acid (20-HETEs) by CYP4A and CYP4F enzymes could impact hyperoxic lung injury via the vasodilating effects of 20-HETE. CYP2E1 and CYP2A enzymes may contribute to the oxidative stress in the lungs caused by ethanol- and nicotine-metabolism, respectively.

EXPERT OPINION

Overall, the CYP enzymes, depending upon the isoform, play a contributory or protective role in hyperoxic lung injury, and are, therefore, ideal candidates for developing drugs that can treat oxygen-mediated lung injury.

Insights into the role of circular RNA in macrophage activation and fibrosis disease

Circular RNAs (circRNAs) are single-stranded RNAs which form a covalent bond structure without a 5' cap or a 3' polyadenylated tail, which is deleted through back-splicing. The expression of circRNAs in highly divergent eukaryotes is abundant. With the development of high-throughput sequencing, the mysteries of circRNAs have gradually been revealed. Increased attention has been paid to determining their biological functions and whether their changed expression profiles are linked to disease progression. Functionally, circRNAs have been shown to act as miRNA sponges or nuclear transcription factor regulators, and to play a part in RNA splicing. Various types of circRNAs have been discovered to be differentially expressed under steady physiological and pathological conditions. Recently, several studies have focused on the roles of circRNAs in macrophages on inflammatory stimulation. In this study, we review the current advances in the understanding of circRNAs in macrophages under various pathological conditions, in particular during organ fibrosis, and summarize possible directions for future circRNA applications.

CircRNA-012091/PPP1R13B-mediated Lung Fibrotic Response in Silicosis via Endoplasmic Reticulum Stress and Autophagy

Silicosis is a progressive fibrotic disease of lung tissue caused by long-term inhalation of SiO₂. However, relatively few studies of the direct effects of SiO₂ on lung fibroblasts have been performed. PPP1R13B is a major member of the apoptosis-stimulating proteins of the p53 family, but its role in pulmonary fibrosis is unclear. To elucidate the role of PPP1R13B in the pathological process of silicosis, we explored the molecular mechanisms related to PPP1R13B and the functional effects of proliferation and migration of fibroblasts. Through lentivirus transfection, Western blotting, and fluorescent in situ hybridization experiments, we found that SiO₂ downregulated circRNA-012091 (circ-012091) expression in lung fibroblasts and induced upregulation of downstream PPP1R13B. Transfection of L929 cells with PPP1R13B CRISPR NIC plasmid inhibited the upregulation of endoplasmic reticulum stress (ERS) and autophagy-related protein expression in lung fibroblasts treated with SiO₂, and induced decreases in cell proliferation, migration, and viability. Transfection of L929 cells with the PPP1R13B CRISPR ACT plasmid induced increases in cell proliferation, migration, and viability. In addition, the ERS inhibitor salubrinal and the autophagy inhibitor 3-methyladenine inhibited the increased migration of L929 cells transfected with the PPP1R13B CRISPR ACT plasmid. These results suggest that PPP1R13B regulated by circ-012091 promotes the proliferation and migration of lung fibroblasts through ERS and autophagy, and plays a crucial role in the development of pulmonary fibrosis in silicosis.

Nano-puerarin regulates tumor microenvironment and facilitates chemo- and immunotherapy in murine triple negative breast cancer model

Tumor associated fibroblasts (TAFs) are key stromal cells mediating the desmoplastic reaction and being partially responsible for the drug-resistance and immunosuppressive microenvironment formation in solid tumors. Delivery of genotoxic drugs off-targetedly to kill TAFs results in production of Wnt16 which renders the neighboring tumor cells drug resistant as shown in our previous study (PMC4623876). Our current approach looks for means to deactivate, rather than kill, TAFs. Reactive oxygen species (ROS) are the central hub of multiple profibrogenic pathways and indispensable for TAFs activation. Herein, puerarin was identified to effectively downregulate ROS production in the activated myofibroblast. In this study, a novel puerarin nanoemulsion (nanoPue) was developed to improve the solubility and bioavailability of puerarin. NanoPue significantly deactivated the stromal microenvironment (e.g., ~6-fold reduction of TAFs in nanoPue treated mice compared with the PBS control, p < 0.0001) and facilitated chemotherapy effect of nano-paclitaxel in the desmoplastic triple-negative breast cancer (TNBC) model. Moreover, the removal of the physical barrier increased intra-tumoral infiltration of cytotoxic T cell by 2-fold. This activated immune microenvironment allowed nanoPue to synergize PD-L1 blockade therapy in TNBC model.

[Progression of Anti-oxygen Therapy in Radiation-Induced Lung Injury]

放射性肺损伤（radiation induced lung injury, RILI）是临床上胸部肿瘤患者放疗后发生的严重并发症，主要表现为气短、低热、咳嗽等，严重影响患者生存，如何更好地防治RILI是亟待探索的问题。RILI的发生机制主要包括靶细胞学说、细胞因子学说、自由基学说、血管内皮细胞损伤学说。其中放疗产生的活性氧（reactive oxygen species, ROS）对组织的损伤贯穿整个RILI病程，对放射性肺炎和放射性肺纤维化均具有直接促进作用。包括巯基化合物、抗氧化酶、植物抗氧化剂等在内的治疗手段已被用于防治RILI，本文即就抗氧化治疗在RILI中的研究与应用作一综述。

Cellular Stress Responses in Radiotherapy

Radiotherapy is one of the major cancer treatment strategies. Exposure to penetrating radiation causes cellular stress, directly or indirectly, due to the generation of reactive oxygen species, DNA damage, and subcellular organelle damage and autophagy. These radiation-induced damage responses cooperatively contribute to cancer cell death, but paradoxically, radiotherapy also causes the activation of damage-repair and survival signaling to alleviate radiation-induced cytotoxic effects in a small percentage of cancer cells, and these activations are responsible for tumor radio-resistance. The present study describes the molecular mechanisms responsible for radiation-induced cellular stress response and radioresistance, and the therapeutic approaches used to overcome radioresistance.

Radiotherapy in combination with hyperthermia suppresses lung cancer progression via increased NR4A3 and KLF11 expression

Purpose: Hyperthermia (HT), a clinical treatment involving delivery of heat to tumors, has been used in combination with traditional chemotherapy and radiotherapy to enhance their effects. However, the molecular mechanism underlying the high efficacy of combination therapy is not clear. This study was conducted to identify the molecular mechanism underlying the sensitization of lung cancer to radiotherapy by HT.Materials and methods: Nuclear receptor subfamily 4, group A, member 3 (NR4A3) and Krüppel-like factor 11 (KLF11) expression in non-small-cell lung cancer cells was confirmed by performing real-time quantitative reverse transcription-polymerase chain reaction. Tumor cell proliferation and apoptosis were assessed via a colony-forming assay and Annexin V/propidium iodide staining.Results and conclusions: Expression profile analysis revealed elevated levels of NR4A3 and KLF11 in A549 lung cancer cells after treatment with HT combined with radiation. We also confirmed that NR4A3 and KLF11 induced apoptosis and inhibited cell proliferation by elevating intracellular reactive oxygen species levels. Knockdown of NR4A3 or KLF11 using siRNA led to decreased effects of radiohyperthermia. Finally, the effect of these two factors on lung cancer progression was evaluated by in vivo xenograft studies. Taken together, the results suggest that NR4A3 and KLF11 are critical for increasing the efficacy of radiotherapy in combination with HT.

Decreased FBP1 expression rewires metabolic processes affecting aggressiveness of glioblastoma

Radiotherapy is a standard treatment option for patients with glioblastoma (GBM). Although it has high therapeutic efficacy, some proportion of the tumor cells that survive after radiotherapy may cause side effects. In this study, we found that fructose 1,6-bisphosphatase 1 (FBP1), a rate-limiting enzyme in gluconeogenesis, was downregulated upon treatment with ionizing radiation (IR). Ets1, which was found to be overexpressed in IR-induced infiltrating GBM, was suggested to be a transcriptional repressor of FBP1. Furthermore, glucose uptake and extracellular acidification rates were increased upon FBP1 downregulation, which indicated an elevated glycolysis level. We found that emodin, an inhibitor of phosphoglycerate mutase 1 derived from natural substances, significantly suppressed the glycolysis rate and IR-induced GBM migration in in vivo orthotopic xenograft mouse models. We propose that the reduced FBP1 level reprogrammed the metabolic state of GBM cells, and thus, FBP1 is a potential therapeutic target regulating GBM metabolism following radiotherapy.

TFAP2C increases cell proliferation by downregulating GADD45B and PMAIP1 in non-small cell lung cancer cells

Background

Non-small cell lung cancer (NSCLC) is one of the leading causes of death in the world. NSCLC diagnosed at an early stage can be highly curable with a positive prognosis, but biomarker limitations make it difficult to diagnose lung cancer at an early stage. To identify biomarkers for lung cancer development, we previously focused on the oncogenic roles of transcription factor TFAP2C in lung cancers and revealed the molecular mechanism of several oncogenes in lung tumorigenesis based on TFAP2C-related microarray analysis.

Results

In this study, we analyzed microarray data to identify tumor suppressor genes and nine genes downregulated by TFAP2C were screened. Among the nine genes, we focused on growth arrest and DNA-damage-inducible beta (GADD45B) and phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1) as representative TFAP2C-regulated tumor suppressor genes. It was observed that overexpressed TFAP2C resulted in inhibition of GADD45B and PMAIP1 expressions at both the mRNA and protein levels in NSCLC cells. In addition, downregulation of GADD45B and PMAIP1 by TFAP2C promoted cell proliferation and cell motility, which are closely associated with NSCLC tumorigenesis.

Conclusion

This study indicates that GADD45B and PMAIP1 could be promising tumor suppressors for NSCLC and might be useful as prognostic markers for use in NSCLC therapy.

Electronic supplementary material

The online version of this article (10.1186/s40659-019-0244-5) contains supplementary material, which is available to authorized users.

Role of Metabolic Reprogramming in Epithelial⁻Mesenchymal Transition (EMT)

Activation of epithelial–mesenchymal transition (EMT) is thought to be an essential step for cancer metastasis. Tumor cells undergo EMT in response to a diverse range of extra- and intracellular stimulants. Recently, it was reported that metabolic shifts control EMT progression and induce tumor aggressiveness. In this review, we summarize the involvement of altered glucose, lipid, and amino acid metabolic enzyme expression and the underlying molecular mechanisms in EMT induction in tumor cells. Moreover, we propose that metabolic regulation through gene-specific or pharmacological inhibition may suppress EMT and this treatment strategy may be applied to prevent tumor progression and improve anti-tumor therapeutic efficacy. This review presents evidence for the importance of metabolic changes in tumor progression and emphasizes the need for further studies to better understand tumor metabolism.

Advances in Molecular Mechanisms and Treatment of Radiation-Induced Pulmonary Fibrosis

Radiation-induced pulmonary fibrosis (RIPF) is a common complication in patients with lung cancer and breast cancer after receiving thoracic radiotherapy. The average incidence of RIPF is 16%-28% after radiotherapy. RIPF includes a heterogeneous group of lung disorders characterized by progressive and irreversible destruction of lung architecture and disruption of gas exchange. The clinical signs of RIPF include increasing dyspnea, deteriorating lung function, and accumulation of interstitial fluid, eventually leading to respiratory failure. No medical therapy for RIPF has been approved for routine clinical use despite the apparent need for an effective treatment. Numerous signaling pathways are involved in the initiation and progression of RIPF. Also, various approaches for RIPF treatments have focused on several aspects of the current understanding of the molecular pathology of RIPF. This review used the mechanistic categories of associated cell signaling pathways, epithelial cell dysfunction and senescence, abnormal lung remodeling, and aberrant innate and adaptive immunity to review the published literature on RIPF to date and then to identify potential areas for the effective treatment of RIPF.

LDR-Induced miR-30a and miR-30b Target the PAI-1 Pathway to Control Adverse Effects of NSCLC Radiotherapy

Radiotherapy has been a central part in curing non-small cell lung cancer (NSCLC). However, it is possible that not all of the tumor cells are destroyed by radiation; therefore, it is important to effectively control residual tumor cells that could become aggressive and resistant to radiotherapy. In this study, we aimed to investigate the molecular mechanism of decreased NSCLC radioresistance by low-dose radiation (LDR) pretreatment. The results indicated that miR-30a and miR-30b, which effectively inhibited plasminogen activator inhibitor-1 (PAI-1), were overexpressed by treatment of LDR to NSCLC cells. Phosphorylation of Akt and ERK, the downstream survival signals of PAI-1, was decreased by PAI-1 inhibition. Reduced cell survival and epithelial-mesenchymal transition by PAI-1 inhibition were confirmed in NSCLC cells. Moreover, in vivo orthotopic xenograft mouse models with 7C1 nanoparticles to deliver miRNAs showed that tumor growth and aggressiveness were efficiently decreased by LDR treatment followed by radiotherapy. Taken together, the present study suggested that PAI-1, whose expression is regulated by LDR, was critical for controlling surviving tumor cells after radiotherapy.

Endoplasmic reticulum stress-dependent ROS production mediates synovial myofibroblastic differentiation in the immobilization-induced rat knee joint contracture model

Joint contracture is a common complication for people with joint immobility that involves fibrosis structural alteration in the joint capsule. Considering that endoplasmic reticulum (ER) stress plays a prominent role in the promotion of tissue fibrosis, we investigated whether the unfolded protein response (UPR) contributes to the fibrotic development in immobilization-induced knee joint contractures. Using a non-traumatic rat knee joint contracture model, twelve female Sprague-Dawley rats received knee joint immobilization for a period of 8 weeks. We found that fibrosis protein markers (type I collagen, α-SMA) and UPR (GRP78, ATF6α, XBP1s) markers were parallelly upregulated in rat primary cultured synovial myofibroblasts. In the same cell types, pre-treatment with an ER stress inhibitor, 4-phenylbutyric acid (4-PBA), not only abrogated cytokine TGFβ1 stimulation but also reduced the protein level of UPR. Additionally, high reactive oxygen species (ROS) generation was detected in synovial myofibroblasts through flow cytometry, as expected. Notably, TGFβ1-induced UPR was significantly reduced through the inhibition of ROS with antioxidants. These data suggest that ER stress act as a pro-fibrotic stimulus through the overexpression of ROS in synovial fibroblasts. Interestingly, immunohistochemical results showed an increase in the UPR protein levels both in human acquired joint contractures capsule tissue and in animal knee joint contracture tissue. Together, our findings suggest that ER stress contributes to synovial myofibroblastic differentiation in joint capsule fibrosis and may also serve as a potential therapeutic target in joint contractures.